This article is concerned with the deprivation of patients' liberty while u
ndergoing psychiatric treatment, with special reference to the situation in
Finland. It is based on a review of Finnish law, health care statistics, a
nd empirical and theoretical studies. Relevant research findings from other
countries are also discussed. In Finland, it is required that patients are
cared for by mutual understanding with themselves; coercive measures may b
e applied only if they are necessary for the treatment of the illness, or f
or safeguarding patients' safety or the safety of others. Involuntary psych
iatric hospitalization is closely regulated by the Mental Health Act. Howev
er, the rules concerning the deprivation of liberty during inpatient treatm
ent (by seclusion, restraint and restricted leave) are formulated in very g
eneral terms. Therefore, Finnish psychiatric hospitals have their own polic
ies concerning when and how seclusion may be used. The practice of seclusio
n and the use of restraint therefore vary among the psychiatric hospitals i
n Finland.